1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device, a semiconductor device and an electronic appliance.
2. Description of the Related Art
In recent years, flat panel displays such as liquid crystal display devices and electroluminescence (EL) display devices have attracted attention.
Driving methods of the flat panel displays include a passive matrix method and an active matrix method. An active matrix method has advantages over a passive matrix method in low power consumption, high definition, a large-sized substrate, and the like.
Here, a structural example of an active matrix panel is briefly described with reference to FIGS. 21A and 21B. FIG. 21A illustrates an example of a structure in which a driver circuit is provided using a tape automated bonding (TAB) method.
In FIG. 21A, a pixel portion 2101 in which pixels 2102 are arranged in matrix is formed over a substrate 2100 having an insulating surface. The pixels 2102 are arranged in matrix at intersections of scan lines extending from a scan line side input terminal 2103 and signal lines extending from a signal line side input terminal 2104. Each of the pixels in the pixel portion 2101 is provided with a switching element and a pixel electrode layer connected to the switching element. A typical example of the switching element is a TFT. A gate electrode layer side of the TFT is connected to a scan line, and a source or drain side of the TFT is connected to a signal line. In addition, an IC 2151 included in a driver circuit is connected to a flexible printed circuit (FPC) 2150.
In a structure where a driver circuit is provided outside a panel as in FIG. 21A, it is possible to use a driver circuit formed using a single crystal silicon substrate. However, when a driver circuit is provided in this manner, a manufacturing cost cannot be reduced sufficiently because of necessity of preparing a panel and a driver circuit separately, necessity of a step of connecting the panel and the driver circuit, and the like.
In terms of reduction in cost or the like, a method in which a pixel region and a driver circuit region are formed over the same substrate has been employed (e.g., see Patent Document 1: Japanese Published Patent Application No. H8-6053). FIG. 21B illustrates an example of a structure in which a pixel region and a driver circuit region are formed over the same substrate.